g6 TRANSFORMATIONS OF INSECTS. 



smaller than those of most other larvce, for had they been 

 larger, they would have been in the way in the narrow exca- 

 vated gallery ; the membranous feet also are short, and are not 

 calculated to grasp, but they can adhere strongly to a large 

 surface, and their spines form a complete crown. The head of 

 the larva is covered with a reddish and hard integument, so 

 as to allow a solid foundation for the action of the jaws in 

 grinding the dense tissue of the tree. Curiously enough the 

 labrum, or lip, is not notched as it is in the leaf-eaters, and 

 this fact proves the design that has influenced the development 

 of all the other structures. The body has a soft skin, and is 

 covered with tubercles and a few hairs, which render the larva 

 very sensitive to the touch. The caterpillar produces a small 

 quantity of silk, but not enough to make a comfortable resting- 

 place for the chrysalis, so it utilises the saw-dust which has 

 accumulated during the process of tunnelling and drilling, and 

 forms a comfortable and silken cocoon within, and covers it with 

 the dust outside. The chrysalis resembles those of the other 

 moths in certain respects, but it has an armature which is not 

 merely an ornament, but a most useful mechanism, for it helps 

 the pupa to crawl. Immediately after the transformation 

 into the moth state, the life of the perfect insect is more or 

 less endangered, for in traversing the gallery made when it 

 was a caterpillar, it might be severely scratched, and its wings 

 spoiled. But the enveloping skin of the chrysalis, with its 

 spines and sharp points, acts like a suit of armour to the 

 Scsia, which has just got its legs into the world. The insect 

 drags its body slowly along, and finally reaches the open air, 

 and extricates itself and flies away, leaving the skin behind 

 stuck in the hole. In the engraving of the metamorphoses of 

 Scsia apifonnis, the moth on the tree has just escaped from 

 the chrysalis case in the hole below. A larva is shown in its 

 gallery, and two cocoons also. 



The Zygccnida; have some likeness to the Scsiida:, and are 

 very common in southern Europe, some being found, however, in 

 France and Great Britain. The moths fly by day, and like the 

 sun and the bright flowers ; they are a sluggish set, however, and 

 this peculiarity is found in the larva as well. Some of thsm have 



